The field of the invention is dry powder inhalers.
Certain medicines may be inhaled in dry powder form directly into the lungs. Inhalation bypasses the digestive system and avoids any potential metabolic inactivation or destruction of the medicine by the digestive system. Inhalation can also provide very rapid onset of the effect of the medicine. Inhalation may also allow smaller doses to be used to achieve the same desired results as orally ingested medicines. In other cases, it provides a delivery technique for medicines that display unacceptable side effects when taken by other methods. In addition, inhalation also avoids the potential risks of injection to both medical caregivers and patients.
Various inhaler designs have been proposed, to allow dry powder medicines to be inhaled. Most of these inhalers are metered dose inhalers or multiple dose dry powder inhalers. Metered dose inhalers dispense a suspension of powder particles in a compressed propellant gas. Multiple dose dry powder inhalers generally repeatedly dispense individual doses from a bulk powder reservoir, or from a blister disk or cassette. However, certain medicines, such as certain peptides or proteins, or medicines such as vaccines, antidotes, etc., are generally taken by a patient infrequently or even only one time. Metered dose inhalers and multiple dose dry powder inhalers are not intended or well designed for one-time use, to deliver a single dose. These types of inhalers are typically too bulky, costly, inefficient, or difficult to use, when only a single dose is desired, and where the inhaler can be practically discarded after use, in an environmentally acceptable way.
Several unit dose inhalers, intended for one-time use, have been proposed. However, they have not achieved widespread use. Disadvantages remain with unit dose inhalers relating to powder storage, dose uniformity, dispersion performance, ease of use, cost, and other factors. Accordingly, there is a need for an improved inhaler for efficiently providing a single dose of a powdered drug.
It is an object of the invention to provide such an improved unit dose dry powder inhaler.